Self-locking shackle seal



Jan' 20,1959 I w.J. DICKEY ETAL 2,869,911

SELF--LOCKING SHACKLE SEAL Filed May 31, 1955 Eig] .they close andremain in a floating position United States Patent z,s69,911 lSELF-LOCKING {SHACKLE SEAL Wallace I. Dickey, St. Charles Township, KaneCounty,

`and Kenneth R. McClure, St. Charles, lll., said Kenneth R. McClureassignor to'said Wallace J. Dickey Application May 31, 1955, Serial No.512,015 Claims. (Cl. 292-324) objective is economy in manufacture.Attempts to meet both Objectives have resulted in a wide variety ofseals over the course of time. j

One of the effective structures for the self-locking mechanism is thetype shown in Mackey No. 2,343,564 in which the insertion of the freeend of a shackle strip into y.a casingwherein the other end is anchored,displaces a pair of opened spring split rings into a position where y swhich locks the said inserted end against withdrawal.l The lockingstructure is housed in a casing which generally has a seam or jointsubject to being opened by-unlawful tampering, but subject to unlawfulrepair to conceal tampering, for example, by soldering. The presentinvention `may employ numerous self-locking structures, but theabovedescribed type is preferred and is illustrated withf out anyintention `of limiting the invention to it.

' I t is an object of the present invention to provide a sealfhaving acasing. which is tamper-proof to the extent that it is incapable `ofrepair.

l -It is a particular Yobject to provide a casing of metal l which is-not subjecty to repair by soldering technique.

y A further object of the invention is to provide a seamless hollowcasing from a one-piece metal blank.

Y Various other and ancillary objects and advantages of the inventionwill become apparent from the following description and explanation `ofthe improved seal and the method of manufacture shown in theaccompanying drawings in which:

Fig. l illustrates a seal of the present invention as commerciallysupplied.

@and various relationships are possible.

Fig. 2 represents the seal of Fig. 1 in itsfsealing position.

Fig. 3 is a cross-section on the line 3-'3 of Fig. 2.

Fig. iis an enlarged vertical cross-section of the casing on line 4-4 ofFig. l. f

Fig. 5 is a horizontal cross-section o f thecasingfof YFig. 4 showing in`plan viewthe interior locking structure.

. Fig. -6 is an enlarged andl modified form of the folded elementofFigs. 4 and 5.

j Fig. 7 is a front view of the die shown in Fig. -8 for forming thecasing about its yinterior parts.`

Fig. 8 is a vertical cross-section of the die online 8--8 vot-Fig. 7.

ln accordance with the present invention, the easing -is'made from av'one-piece blank of sheet met-al so that therefare no seams orjointsfwhich may be opened in a 'fmanner t permit repair and concealment'of tampering. An additional, although optional feature, is the use of4a metal which is not easily soldered, vsuch as magnesium or aluminum andwhich is Amore easilyworked mechanically toconv'er'tthesheet'metal'linto hollow casing form;

rwice The seal has a hollow casing 10 of one piece of metal, preferablyin the form of an approximate sphere, and preferably of aluminum. A slot11 thereinis llanked in Fig. l by a pair of wings 12 and 13 which arenonfunctional, yet a desirable result from the method of manufacture.Each wing is a at folded piece of two layers of metal comprising excessmetal from an original tubular form that is swaged into substantiallyhemispherical form in the nal act of closing the casing 10 inmanufacture. The wings may be cut away, but it is preferred to retainthem, since the edges 14 thereof are folds, making access to theinterior very diflicult by separating the layers of a wing. Should thelayers forming said wings be spread apart the tampering would be readilyapparent,

Emerging from the slot 11 is at its free end 16 to narrow the widththereof. The free end of the strip -15 has a detent structure tocoopcrate with means in the casing to lock the end within the casing.The preferred detent structure is [shown as a hole 17 positioned toregister with a similar hole or holes within the casing when using thepreferred locking means as later described.

Also emerging Vfrom the slot 11 is a strip 1S `superimposed over thestrip 15 and so mounted as to provide a space 19 between them into whichthe said free end 16 of the shackle may be inserted. The strip 18projects a slight distance from the casing so that the two superimposedstrips provide a guide to facilitate inserting the free end 16 betweenthem.

It is preferred that the strips l5 and :18 be integral v This mayfbeeffected by folding heet material to `bring to areas thereof face toface to'provide the superimposed strips between which the free end -isinserted. As shown, the two spaced pieces of metal are ymade integral byfolding a piece with a wider end portion along an edge to form a fold2i) in extension -of the edge of strip i5. The fold 20 functionssomewhat as the bottom of a channel of which the strips 15 and '1S arethe channel flanges, and of which the width of the channel is the space19 to receive the free end 16 of the strip 15.

Within the casing 10, the strips 15 and 18 at their ends make contactwith the rear wall of casing 1t) and have registering terminalvelongated recesses 22 and 23, forwardly of which are registering holes24 and 25 to register with the hole 17 in the locked position.

Forwardly of the holes 24 and 25 on each strip are areas on which liethe ends of split rings-26 and 27. These rings are held open by one orboth of the pieces of metal, or as shown, by the described channelstructure and on' being moved toward the rear of the casing10 the ringends enter the holes 24E-.and 25 and close. When the free end 1d of thestrip 15 is inserted into the casing, it pushes the ring portions 28which *lie in the recesses22 yand 23 toward the rear of the casing andwhen therings reach the holes 24 and 25, the hole 17 is ,positioned "toobstacles may be provided by a single depression orby two upset ridges.

Gn atleast one of the strips l5 and 1S, the areawhich normaily holds thesplit rings in their sensitive position is depressed as shown at 2? inFigs. '4 and 5 forwardly a metal strip 15 tapered` 3 from a hole 24 or25 to provide by its edges lateral obstructions and thus prevent therings from being laterally displaced from their intended line of motionfor locking. In Fig. 6, the depression is lacking and two vupset ridges30 are formed substantially tangent to a hole 24 or 25.

To hold the strips 15 and 18 in the casing against withdrawal, anchoringmeans is provided.l In one form,

at least one and preferably both of the strips 15 and 18 have outturnedears 31 and 32, struck from the middle of the strip. These ears arepositioned and bent so as to lie against the interior forward wall ofthe casing when the casing is formed about the locking structure. InFig. 6, another form of detent is shown, which may be substituted forthe ears 31-32, but which is preferably used to supplement the functionof said ears. Recess 33 in the edge of one, and preferably both, of thestrips opposite the fold 20 is formed at a location to receive metal asthe casing is being formed about the locking structure. Although a likerecess may be made in the fold-edge opposite recess 33 for the samefunction, it is preferred to maintain the fold 20 unbroken as a guidingway for inserting the free end 16.

In manufacture, the locking means of the kind illus trated, or of anyother form, is assembled and the casing is formed around the lockingstructure. One manner of accomplishing this is to form iirst from sheetlmetal in any well-known manner a tubular form with one closed end andan open end, such as the cylindrical thimble 40 having a substantiallyhemispherical end 41 and an open ended tubular body 42 of suitablelength to be closed as now described. The thimble 40 is placed in atwo-part die-block having upper section 45 and lower section 46 andforming between them a space 47 of size exactly to house the thimble 40.The space 47 opens to the rear of the die-block to receive a closettingplunger 48 with a recess 49 in its end to t the end 41 of thimble 46.The forward end of the space 47 isrounded, preferably in hemisphericalform, and functions to swage the thimble body 42 into a rounded closureform when the plunger 48 feeds the thimble forwardly in the die-block,`into which the assembled locking structure has been placed. The thimble40 is l preferably of a length so that the two hemispherical closureforms are complementary to form a spherical casing.

The forward end of the die-block has a slot 51 located at the interfaceof the two sections to receive the strips 1'5 and 18 and lateralextensions 52 and 53 of the slot The thrust of the plunger 48 must beaccurately guaged so that when the swaging is completed the resultingslot 11 formed by the top edge of the thimble 40 has the proper width topermit inserting the free end 16 of the strip 15 between itself andstrip 18.

In the form of Fig. 4, the ears 31 and 32 are preformed in position tolie within the casing wall to be formed between them and the die. In theform of Fig. 6, the recess 33 may be duplicated on the opposite edge,and then the ears 31 and 32 may be omitted. The one or two recesses 33are positioned to receive the casing metal being shaped, and since suchentry of the casing metal into a recess 33 will shorten the slot 11 intowhich the free end 16 is to be inserted, the said free end must besuflciently narrow to pass the metal in a recess 33.

In the locking structure. described, it is advantageous to-have thestrips 15 and 18 connected by the fold 20 land to have the resultingchannel project from the casing 10. The slot formed by space 19 and theedges of the casing may be controlled in size so that when the free end16 is locked `within the casing there is no opening, other thaneffective clearance space, into which a tampering probe may be insertedin attempts to open the two rings and unlock the seal. By thisexpedient,

it becomes more diicult to probe into the casing by v way of slot 11between the strips 15 and 18.

From the foregoing, it is to be understood that the seal is not limitedto the exact structure illustrated and described and that numerouschanges and modifications are contemplated as falling within the scopeof the appended claims.

We claim:

l. A shackle seal comprising a hollow casing having a slot opening intothe casing, a metal sealing strip emerging from the casing through onlya portion of said slot and having a free end adapted to enter the casingthrough the remainder of said slot, detent means at said free Vend ofthe strip, means anchoring said strip within the casing, split-ringmeans within the casing for automatically engaging said detent means andthereby locking said free end within the casing upon insertion of saidfree end to a predetermined depth, said casing being formed of one pieceof metal, having a rounded closure form opposite said slot and having arounded closure form containing said slot, said slot being of sizeincapable of passing said ring means from the interior to the exteriorof the casing, said casing having a plurality of integral wingsprojecting therefrom, each wing having two layers of metal in contactand two edges at an angle to each other, one edge being a fold for thetwo layers of metal and the other edge of the wing presenting metaledges of the two layers in continuation of the edges of the Acasingdefining the slot.

2. A shackle seal comprising a hollow casing having a slot opening intothe casing, a metal sealing strip emerging from the casing through onlya portion of said slot and having a free end adapted to enter the casingthrough the remainder of said slot, detent means at said free end of thestrip, means anchoring said strip within the casing, split-ring meanswithin the casing for automatically engaging said detent means andthereby locking said free end within the casing upon insertion of saidfree end to a predetermined depth, said casing being formed of one pieceof metal, having a rounded closure form opposite said slot and having arounded closure form containing said slot, said slot being of sizeinca.- pable of passing said ring means from the interior to theexterior of the casing, said casing having two integral wings projectingtherefrom and alined with said slot, each wing having two layers ofmetal in contact and two edges at an angle to each other, one edge beinga. fold for the two layers of metal and the other edge of Vthe wingpresenting metal edges of the two layers in continuation of the edges'ofthe casing defining the slot.

3. The method of making a self-locking shackle seal with a one-piececasing which comprises deforming a blank of sheet metal to tubular formhaving an open end and a closed end, inserting Within said open endlocking means and two associated spaced pieces of sheet metal of whichone extends away from the two pieces as a shackle strap, and deformingsaid open end of said tubular form about the inserted structure to housethe locking means and to provide entry to the casing through the spacebetween said pieces, and in deforming said open end squeezing excessmetal laterally away from the casing wall as a plurality of wing-formprojections each consisting of two folded-together layers of metal incontact.

4. The method of making a self-locking shackle sealv with a cne-piececasing which comprises deforming a blank of sheet metal to cylindricaltubular form having a substantially hemispherical closed end and an opencircular end, inserting within said open end locking means and twoassociated spaced pieces of sheet metal of which one extends away fromthe two pieces as a shackle strap, and deforming said open end of saidtubular form into a substantially hemispherical form about the insertedstructure to house the locking means and to provide entry to the casingthrough the space between said pieces, and in deforming said open endsqueezing excess metal laterally away from the casing wall as aplurality of wing-form projections each consisting of twofolded-together layers of metal in contact.

5. The method of making a self-locking shackle seal with a one-piececasing which comprises deforming a blank of sheet metal to cylindricalthimble form having a substantially hemispherical closed end and an opencircular end, inserting within said open end locking means and twoassociated spaced pieces of sheet metal of which one extends away fromthe two pieces as a shackle strap, and deforming said opened end of saidthimble form into a substantially hemispherical form substantiallycomplementary to the closed end of the thimble and about the insertedstructure to house the locking means and to provide entry to the casingthrough 6 the space between said pieces, and in deformng said open endsqueezing excess metal laterally away from the forming sphere as twowing-form projections alined with the said two pieces of metal, eachwing consisting of two folded layers of metal in contact.

, References Cited in the tile of this patent UNITED STATES PATENTS447,266 Wilmot et al. Feb. 24, 1891 594,580 Tyden Nov. 30, 1897 629,939Tyden Aug. 1, 1899 777,868 Tyden Dec. 20, 1904 896,244 Reesor Aug. 18,1908 1,016,985 Davis Feb. 13, 1912 1,026,943 Brooks May 21, 19121,106,860 Bayton Aug. 11, 1914 2,454,927 Kalwo Nov. 30, 1948 2,768,848Mitchell et al. Oct. 30, 1956 FOREIGN PATENTS 575,229 Great Britain Feb.8, 1946

